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pISSN : 1975-7700 / eISSN : 2734-0570

2020 KCI Impact Factor : 0.42
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2015, Vol.10, No.1

  • 1.

    A Study of the Security assessment methodology for Android Mobile App

    Kim Kyoung Gon | Kim, Huy Kang | Kim, Eunjin | 2015, 10(1) | pp.1~16 | number of Cited : 0
    Abstract PDF
    Apple iPhone was released on 2007, and Android 1.0 with alpha version was released in November of the same year. After seven years, in 2013, about 50 billion apps were downloaded from Android which tells that the mobile apps users were dramatically increased. Company also have developed and distributed mobile app to provide their service to users. As the number of mobile apps rapidlly increased, many mobile apps are still developed with vulnerability and distributed in markets due to the limitations of security assessment. Hackers usually repackag Apps and distribute the malicious Apps via Appstore or Googleplay in order to infect many devices. In this paper, we selected four mobile app security assessment methodologies. Local government, local private company, global security research institution and global consulting firm’s methodologies were selected. Android-based mobile app security assessment methodology was developed for the security personnel to develop and operate in their organization. Mobile app security assessments methodology consists of 3 areas and 9 sub items and added menu assessments approach. We conducted the assessment using this methodology for the major domestic tele-communication company and found out that the assessment methodology developed for Android mobile app was efficiently assessed without missing any items compared to existing assessment methodologies
  • 2.

    Image Based Surface Visualization Method for the Defects Detection

    Kwangseok Lee | 한학용 | 2015, 10(1) | pp.17~24 | number of Cited : 0
    Abstract PDF
    Defects detection on the final product of camera module is a major issue in the visual inspection industry. This paper is about the study of surface visualization for foreign material detector or abnormal lens surface between IR filter and lens in camera module. With the purpose of making filter surface noticeable, it extracts background image assumed as polynomial expression in input image and then generate the differential image of input image. Also, it accentuates flexuosity of surface, applying median filtering with high precision, after it smoothes a set of pixels that has recursively similar brightness value based on coarse-to-fine strategy known as bilateral filtering. Performance of the proposed method has been evaluated on some sample images captured in the white light. As a result of the experiment, we verified that surface condition is visualized and surface defects such as foreign substance is identified distinctly. And this method is expected to be used widely in the machine vision industry for automated or manual visual inspection of defects system.
  • 3.

    A Design and Implementation of Real-time Safety Diagnosis Evaluation System Using the Dynamic Response Signal Information of Building

    HyunJu Kim | Kim Chang Geun | Seok Hyung Yoo | 2015, 10(1) | pp.25~33 | number of Cited : 1
    Abstract PDF
    National Emergency Management Agency in Korea recently made it obligatory to install seismic acceleration sensor for the seismic safety diagnosis of buildings. This can be used to analyze the effects of the disaster on the building structures by measuring the magnitude of the seismic acceleration, and to evaluate the soundness of the building structure and determine the safety grade of the building. In addition, it is used as the data for studies and technical development to establish earthquake countermeasures and mitigate the seismic disaster. In this study, a real-time structure safety diagnosis and evaluation system are proposed and implemented based on the natural period change and maximum inter-story drift, which are dynamic characteristic data. The natural period change data in the proposed system include the information about the change in the rigidity of the damaged structure, and the maximum inter-story drift data include the inter-story displacement due to the reduced rigidity of the damaged structure. Based on the two kinds of data, the system was designed and implemented so that the soundness of the building was subjected to a disaster can be evaluated in real time, and warning signals can also be automatically propagated according to the evaluation results.
  • 4.

    The Effect of Emotional Consumption Value on Risk-taking : focus on SmartTV

    Sung-Hwi Kwag | Lee Sang Joon | 이경락 | 2015, 10(1) | pp.35~45 | number of Cited : 2
    Abstract PDF
    Smart paradigm of IT has an impact on not only smart phones but also on overall society and culture like smart work and smart life, and it drive the traditional TV into Smart TV. While the rational consumption behavior had received higher attention in the past of consumer behavior research, the study of emotional consumption behavior and risk-taking was inadequate. This tendency of the research was also same on the field of acceptance of innovative products, digital and convergence and technical goods. In this paper, we intended to identify the relationship between importance of consumer sensibility as a factor of decision-making and risk-taking characteristics of consumer by revealing the relationship between individual characteristics, emotional consumption value, risk-taking and purchase of new products. We set the hypotheses for the relationship between the impact of complexity, cost irrationality, usefulness, emotional consumption value of Smart TV on the risk-taking and acceptance of new product, and verified it. As a result, we found the role of risk-taking on consumer behavior that complexity and emotional consumption value affect risk-taking, and risk-taking affect the purchase intention of Smart TV. However, cost irrationality and usefulness has no significant effect on risk-taking.
  • 5.

    Analysis of Spectral Characteristics of Audio Object for Enhancement of Spatial Audio Object Coding

    Kwangki Kim | 2015, 10(1) | pp.47~54 | number of Cited : 0
    Abstract PDF
    This paper describes a method that can enhance the performance of spatial audio object coding (SAOC) with two-step coding structure to make a multi-object based audio service with users' interaction. In the proposed method, frequency bands and bit-rate of a residual signal can be variably decided by analysing the spectral characteristics of a specific audio object such as vocal object to efficiently handle the residual signal which is used to precisely control the specific audio object. The proposed method divided the frequency band of the specific audio object into five frequency regions including silence according to the spectral characteristics of the specific audio object. From the analysis result, most audio objects including vocal object have about more than 20 percents low frequency region compared with the original fixed frequency band to be 0 to 5.5 kHz. Consequently, the proposed method showed the high bit-rate reduction of about 28.6 percents for test items and about more than 10 percents for audio objects. Especially, since the bit-rate of the vocal object which is mainly used in KARAOKE application scenario can be greatly reduced as about 15 percents, it can be confirmed that the proposed method can enhance the original SAOC with two-step coding structure.
  • 6.

    Iterative OSTBC-based Multi-User MIMO Interference Cancellation for Uplink Systems

    김진관 | Kwangmin Hyun | SangKyu Park | 2015, 10(1) | pp.55~68 | number of Cited : 0
    Abstract PDF
    In next-generation wireless communication systems, high-rate data transmission is required with the multimedia contents. Therefore, the wireless communication technology of high channel capacity is required. The Multiple antenna wireless communication systems have recently significant attention due to their higher capacity and better immunity to fading. Multi-user multiple-input multiple-output (MIMO) uplink transmission system has a trade-off between multiplexing and diversity scheme. There are several methods for obtaining the diversity gain in a special space multiplexing technique. Orthogonal space-time block codes (OSTBC) can be obtained diversity gain by reducing the muti-user interference (MUI). In space-time code, OSTBC scheme is the best method to simplify encoding and decoding and improves the diversity gain. This scheme is used by reducing the MUI in a wireless communication system. However, it is only applicable for downlink transmission. In uplink transmission system, one method that tried to reduce MUI using the unitary property of OSTBC configured the same number of receive antennas with the number of users at the base station, and each receive antenna could detect only single user signal. Therefore, even when equipped with multiple number of receive antennas larger than the number of users, receiver diversity gain can not be obtained. In this paper, we propose an interference cancellation detector with a simple decoding structure for a multi-user MIMO uplink transmission system that utilizes the equivalent channel of each user using the special property of the OSTBC. The proposed OSTBC-based interference cancellation algorithm reduces interferences received from the other users, and simultaneously diversity gain can be achieved. The simulation results validate the proposed algorithm in terms of the bit error rate (BER) performance.
  • 7.

    Selectivity Estimation Using Frequent Itemset Mining

    엄보윤 | Christopher Jermaine | 이춘화 | 2015, 10(1) | pp.69~78 | number of Cited : 0
    Abstract PDF
    In query processing, query optimization is an important function of a database management system since overall query execution time can be significantly affected by the quality of the plan chosen by the query optimizer. Under cost-based optimization, a query optimizer estimates the cost for every possible query plans based on the underlying data distribution in synopses of database relations. The most common synopses in commercial databases have been histograms. However, when there is correlation among datum, one-dimensional histograms can provide poor estimation quality. Motivated by this, we propose a new approach to perform more accurate selectivity estimation, even for correlated data. To deal with the correlation that may exist among datum, we adopt well-known techniques in data mining and extract attribute values that occur together frequently using frequent itemsets mining. Through experimentation, we found that our approach is effective in modeling correlations and that this method approximates intermediate relations more accurately. In fact, it gives precise estimates, particularly for the correlated data.
  • 8.

    Modified QRM-ML Detection by Stage Reduction in MIMO Systems

    Gunyoung Ko | SangKyu Park | Kwangmin Hyun | 2015, 10(1) | pp.79~87 | number of Cited : 1
    Abstract PDF
    In this paper, modified QRM-ML detection algorithm is proposed to reduce computational complexity of the conventional QRM-ML detection algorithm in MIMO systems. We consider a stage reduction algorithm to QRM-ML detection algorithm and arrange all steps of each stage and computational complexity, which is calculated the number of multiplications per each step. The proposed detection algorithm has lower complexity than full candidates of QRM-ML detection algorithm. It also has no saturation on BER performance and better performance in high SNR than QRM-ML detection algorithm of lower candidates, which has a similar complexity to proposed algorithm. We also set a new arbitrary parameter which can adjust the number of reduced stages, and it can be selected by considering a trade-off relationship between BER performance and computational complexity. A stage reduction algorithm and each detection algorithm are presented in a row and compared in terms of BER performance and computational complexity by numerical results and experimentations. In the process of experimentations, the cross points of conventional QRM-ML detection algorithm and modified QRM-ML detection algorithm in BER performance graphs are also analyzed in diverse situations and compared in terms of efficiency of proposed algorithm according to the number of antennas and modulation order.
  • 9.

    Application Development for Sports Activation on Information-Oriented Period

    김용학 | Park Seung byeol | 2015, 10(1) | pp.89~101 | number of Cited : 2
    Abstract PDF
    With the arousal of smart media era, the thought of information has now changed into something that can develop the individuals and organization even when it is communicated and shared. In the digital media, smart media environment which utilizes bilateral communication and various form of expression, contrary to conventional media environment which is a one-way transmission of information, delivery of information message by causing user's interest and softwares' contents is gaining more attention. Development of application which can promote sports activation in the information-oriented period could be the method. In this paper, when sports spectators view soccer, basketball, baseball in this information-oriented society, it not only informs the sports game, player's information, weather according to time, but also sets the function for the user to acknowledge his/her own location wherever they access, and establishes the function of conveniently notifying the information for sports matches in weekly and monthly basis.
  • 10.

    Improved Cholesky Decomposition using Channel Element Relocation for MIMO Systems

    Jinhyeuk Shon | SangKyu Park | Kwangmin Hyun | 2015, 10(1) | pp.103~112 | number of Cited : 0
    Abstract PDF
    This paper newly proposed a channel element relocation which can reduces multiplication complexity of ML by applying cholesky decomposition. In wireless communication, maximum likelihood(ML) detection scheme that shows the best bit error rate(BER) performance is usually used; however, a huge amount of multiplication complexity has been pointed out as a default. To lower multiplication complexity of ML detection scheme, various methods have been proposed. Among of them, QRM-MLD algorithm which uses QR decomposition was proposed. The QRM-MLD algorithm maintains the optimal BER performance of ML and reduces the huge amount of multiplication complexity of ML detection. But, QR decomposition shows a huge increase according to augmentation of a number of antennas because of amount of complexity of decomposition process of QR decomposition. For this reason, cholesky decomposition which has low complexity on decomposition process was proposed. Cholesky decomposition does not have high complexity on decomposition process but show reduced complexity than QR decomposition when a number of antennas increase. However, despite reduced complexity, there is a need of additional decrease of ML complexity. To satisfy the need, this paper proposes channel element relocation which applies to Cholesky decomposition and shows additional complexity reduction. Comparision with proposed method and QRM-MLD and conventional Cholesky decomposition shows that proposed method has low complexity.
  • 11.

    An Efficient Architecture by Organizing Streaming and Storage Users Position in P2P Network for Sharing Live Video

    TRAN THI THU HA | Jang, Byeong-Ok | 2015, 10(1) | pp.113~120 | number of Cited : 0
    Abstract PDF
    Peer-to-Peer (P2P) streaming is a method for sharing data on the network without the support of server. One of the main challenge is to provide a high quality of service through the dynamic behavior of the network because a user may join or leave anytime. We realized that the streaming users- who use mobile devices with 3G/4G connection, may stop watching live video after a while if they find the video is out of their interest. Users leaving causes dynamic and affect the data delivery. On the other hand, the storage users-who use PC with wired Internet, are downloading the video do not have the concern of interest and playback quality, until they start to watch the video. Hence, the storage users are relatively more stable than streaming users. This paper, we propose an efficient architecture by organizing storage users position are closer to the broadcaster than streaming users position. And then, we apply our idea on hybrid model that combines the benefits of tree-based and mesh-based models to decrease startup delay, packet lost and control overhead compare with other systems.
  • 12.

    A Study on Software Education Method for girls with MadewithCode

    Shin, Seungki | 최익선 | Bae Youngkwon | 2015, 10(1) | pp.121~136 | number of Cited : 3
    Abstract PDF
    Korea government declared 2014 year as the first year of profound Software Education. Since 2015, Software Education will be held in schools with the beginning with middle school as a regular and independent subject. Software Education is learner-centered teaching and learning methods for enhancing the creativity and problem solving skills through computer programming based on computational thinking. However, in terms of the existing computer programming research, the lack of the considering the gender issue, which is one of the learner’s characteristics, is often exposed in the computer programming education field. For this reason, MadewithCode developed by Google is a programming language designed to increase participation by women is more related to the software field. In this study, we have examined what MadewithCode is in terms of its attributes and features, once we have applied this programming language to both forth and sixth grade in elementary school, then we conducted surveys and analyzed the satisfaction appeared to girl through t-test statistic method. As a result, female students showed higher results than boys in the affective domain of interest. In a comparative study between the grade, forth grade female students showed high results in cognitive, affective and behavioral areas than sixth grade girls. In addition, the results indicated that the students got a keen interesting the feasibility as a school subject about computer programming language. Finally, on the basis of the results presented in this study, the direction for the future software education of Korea was suggested.
  • 13.

    Research on the Sensor-based System for Improving the Safety of Electric Wheelchair

    Jungdae Kim | 2015, 10(1) | pp.137~143 | number of Cited : 2
    Abstract PDF
    In this paper, we propose a system that allows users to move more safely in a variety of terrain using an electric wheelchair. Developing from previous paper “Intelligent Powered Wheelchair'” in which the ability to avoid obstacles using the laser sensor, wheelchair automatically avoid the obstacles using listening to the sound. Thus, this paper uses the sensor-based topography and controls the motor speed of the electric wheelchair according to the terrain. When normally using a power wheelchair to change fast speed suddenly, the electric wheelchair overturned, and the user happens to fall in the future. In this case, because of the center of gravity of the wheelchair due to a sudden change in the law of momentum maintaining, it occurs dangerous for users. In addition, if wheel chair does not pass through the flat terrain and to safely pass the terrain changed by controlling the motor speed in order to reduce speed slowly. The sensor was used as an acceleration sensor and a gyro sensor by using a Kalman filter to output a correct angular value. In this paper, by providing SOS service system help to receive quickly the displaying the location map, users can predefine if the button is clicked, or need urgent help. The user's location using a GPS signal and Google API was built in the smart phone, GPS’s information identify the location of the user. In addition, the user's locations and user’s data are saved on the server that is responsible for managing in real time, if new users request and receive the notification signal analysis, they can ask the people who previously registered via message or email.